Reilly was on the receiving end of a hit from physical Sabres forward Jordan Greenway. While the hit itself was clean, Reilly did not receive it well, awkwardly falling to the ice, ultimately hitting his head first. He immediately appeared to be knocked out as he lay motionless on the ice for several moments. Luckily, the officials blew the play dead quickly, allowing help to get on the ice.
The training staff for both the Islanders and the Sabres all came out onto the ice, making it four medical staff who were taking after him in the immediate aftermath of the play. He was in a bad spot and was disoriented after the play. The stretcher did come out for him but in the end, they decided not to use it.
Luckily, he was able to get off the ice albeit very slowly, and with the help of the trainers and his teammates, who supported his weight on his way to the bench. Meanwhile, players from both teams gave him stick taps, including Greenway, who must have felt terrible about the result.
With any luck, Reilly will not have any lasting impacts from this play. It seems very likely that he has a concussion, but the fact that he was able to get up and move means the worst-case scenario was certainly avoided. Hopefully, he will make a quick recovery and return to the Islanders lineup before we know it.